Why are Submarines Black and Cruise Ships White?

Added: 2026-05-25

[00:00:00]Have you ever gone to the beach and noticed tourist ships crowded together at the harbor? Did you spot anything strange about them?

[00:00:08]If you watch long enough, you'll realize they are almost always painted the same color, white. Pretty strange, isn't it?

[00:00:15]And it's not just tourist ships. Even military vessels like submarines seem to follow the same pattern. No matter which country they come from, they are almost always coated in the same solid black color. In theory, people could paint ships in all kinds of different colors, just like they [music] do with flags or military uniforms. But strangely enough, ships around the world tend to look nearly identical in color, as if they were all following some unwritten rule.

[00:00:40]So, what exactly is the reason that people don't dare paint ships whatever color they want?

[00:00:45]To understand why choosing a ship's color is such a difficult decision, we first need to look at the environment they operate in. Out in the middle of the ocean, you can't freely choose colors. [music] Because if you choose the wrong one, you won't just lose money. You could lose your life. First, let's talk about submarines. During World War I and World War II, submarines came in all kinds of colors. Gray, ocean blue, green, pink, >> [music] >> and even zebra striped patterns. Sounds pretty bizarre, doesn't it? The reason was that submarine engines at the time were still very primitive.

[00:01:18]>> [music] >> They constantly needed oxygen from the air to burn diesel fuel.

[00:01:22]As a result, submarines spent 90% of their time traveling near the surface.

[00:01:27]They only truly submerged when attacking. That made early submarines more like surface ships [music] with temporary diving capability, rather than machines that could remain completely hidden beneath the ocean. If you had lived in that era, all you needed was a pair of binoculars on [music] a ship's deck or a helicopter flying overhead to spot an enemy submarine. So, to make them less visible, engineers were forced to experiment with all kinds of paint schemes [music] to help submarines blend into their surroundings. For example, in Germany's North Sea, where the water was murky and full of algae, >> [music] >> submarines were painted green.

[00:02:00]Meanwhile, in the crystal clear blue waters of the Mediterranean, >> [music] >> submarines were painted blue.

[00:02:06]And in Britain, some submarines were even painted pink to make them harder to spot when servicing [music] at dawn or dusk.

[00:02:14]Back then, choosing a submarine's paint color was [music] an extremely strict process.

[00:02:18]Navies constantly took submarines out to sea for testing.

[00:02:22]>> [music] >> They observed them under sunlight and fog and from dozens of kilometers away, all to determine which color made the vessel the hardest to detect. [music] The reason they were so careful was because choosing the wrong color for the environment could be [music] fatal.

[00:02:35]For example, painting a submarine dark blue because the ocean is blue, only to deploy it in the foggy gray waters of the North Sea, the submarine would stand out like a black ink stain against [music] a gray background, sitting directly in the enemy's line of fire.

[00:02:50]So, a ship's paint color is never chosen randomly. It depended heavily on the environment around it.

[00:02:55]>> [music] >> But, you're probably wondering, what about modern submarines?

[00:02:59]Why have they all become completely black?

[00:03:01]>> [music] >> The answer is that the environment changed. During World War II, humans invented sonar technology.

[00:03:08]Instead of using binoculars, warships began sending sound waves down into the water.

[00:03:13]When those sound waves hit a submarine's steel hull, they bounced back.

[00:03:18]Thanks to that, [music] a warship's detection system could determine the submarine's exact location, even from very long distances.

[00:03:25]At that point, no matter what color you painted the submarine, your position [music] could still be exposed. Because of this, engineers stopped focusing on camouflage paint and instead covered submarine hulls with synthetic rubber tiles about 4 mm thick.

[00:03:40]The rubber absorbed most of the sound waves, making the submarine extremely difficult to detect. However, modern submarines can dive hundreds of meters deep. They can remain underwater for hours, even weeks at a time.

[00:03:52]As a [music] result, the outer rubber layer would quickly become deformed under pressure or corroded by salt water. To solve this problem, engineers mixed in a large amount of carbon black.

[00:04:02]You can think of it as a special reinforcing additive.

[00:04:05]Once added, the rubber transformed into a kind [music] of super material, flexible, durable, highly pressure resistant, and able to withstand long-term wear.

[00:04:15]The only issue is that carbon black >> [music] >> is naturally pitch black. Trying to dye it another color would damage its chemical structure. [music] And that's why black hulls became an almost unavoidable choice for modern submarines.

[00:04:28]Sounds pretty harsh, doesn't it?

[00:04:30]Even when something as simple as painting a ship becomes a matter of survival.

[00:04:34]And this doesn't apply only to military vessels. If you look at passenger ships, you'll find a very similar story.

[00:04:40]Their uniform white color is also determined by the environment around them.

[00:04:45]Back in the 19th century, massive passenger liners, the RMS Titanic being the famous example, were usually painted pitch black.

[00:04:53]The reason was simple. Ships at the time were powered by coal. Coal dust spread into every corner of the vessel. If the ship had been painted a light color, it would have looked filthy and stained after just a single day at sea.

[00:05:06]Because of that, black paint became almost mandatory. The downside, however, was extreme heat. Black surfaces absorb up to 90% of the sun's heat energy. And since steel is an excellent conductor of heat, during summer or while crossing the equator, the black steel hull could reach temperatures of 158° to 176° F, enough to burn your hand on contact.

[00:05:30]That heat didn't stay on the outside of the ship. It transferred directly into the passenger cabins, making the rooms inside unbearably hot and stuffy.

[00:05:39]Even so, people couldn't simply switch to another color whenever they wanted.

[00:05:43]It wasn't until ships switched to oil and diesel engines that shipping companies finally had the opportunity to use lighter colors.

[00:05:51]And after many rounds of testing, white was officially chosen.

[00:05:55]That's because white reflects around 80 to 90% of the sun's heat better than almost any other color.

[00:06:01]It helps keep the ship cooler, making passengers inside far more comfortable.

[00:06:06]This is why today it's difficult to find a cruise ship painted any other color.

[00:06:10]Because if owners change the color based purely on personal preference, they could end up paying millions of extra dollars each year in fuel costs just to power cooling systems.

[00:06:20]However, white also has its disadvantages.

[00:06:24]Imagine seawater corroding the ship's hull and creating orange rust streaks.

[00:06:28][music] Against a white surface, they stand out like ugly scars.

[00:06:32]They turn luxurious cruise ships into vessels that look old and worn down in the middle of the ocean.

[00:06:37]This drawback forces shipping companies to spend enormous amounts of money repainting and maintaining the outer hull.

[00:06:44]The estimated cost ranges from hundreds of thousands to several million US dollars, and the [music] work has to be repeated every few years.

[00:06:52]Meanwhile, those maintenance costs would be much lower if the hull were painted a darker color, especially black.

[00:06:58]But ship owners cannot freely change the color because passenger comfort and cool temperatures come first. [music] And that's why white has become the almost default color for cruise ships, even though it comes with a very expensive price tag.

[00:07:11]To give you an even broader perspective, let's take a look at warships.

[00:07:16]Before the 20th century, warships were often painted in very striking colors.

[00:07:20]Glossy black, bright red, even yellow.

[00:07:24]That was because weapons at the time were still primitive, and ships had to get very close to each other before they could fire.

[00:07:30]As a result, there was little need for camouflage or stealth. In fact, painting ships in flashy colors helped intimidate enemies and display the power and prestige of a kingdom's navy at sea.

[00:07:40]But by the early 20th century, naval guns could fire from dozens of kilometers away.

[00:07:45]Whoever was spotted first would be destroyed first.

[00:07:49]That was when navies around the world began treating a ship's paint color as a matter of survival. They experimented with every possible color. And eventually, a shade known as haze gray was chosen because it allowed warships to blend into the horizon under almost every weather condition, sunlight, rain, or fog.

[00:08:07]As a result, today you'll notice that nearly every warship in the world shares the same dull gray color scheme.

[00:08:13]So, in the maritime world, color is not just [music] about fashion. It's also a survival mechanism that allows ships to adapt to the environment around them.

[00:08:22]So, the next time you see ships and their paint colors, remember that behind them lies a harsh story of survival.

[00:08:28]Pretty fascinating, isn't it? And if you're still curious about everyday things that few people truly understand, leave a comment with a topic you'd like me to explain in the next video.

[00:08:37]Thank you all for watching.